In recent years, in the biotechnology industry, the establishment of a technique that can efficiently mass-produce and mass-purify a protein has been desired.
Generally, a protein is produced by culture using a cell strain derived from an animal or a bacterial cell, such as Escherichia coli. Therefore, it is necessary to separate a desired protein from a culture solution and purify the desired protein. Particularly, in order to put a drug utilizing an antibody (antibody drug) to practical use, it is necessary to remove turbid components, such as cell debris, and non-turbid components, such as dissolved proteins derived from cells, from a cell culture solution and purify to purity sufficient for human treatment applications. In the purification step, a protein-adsorbing material, such as a protein-adsorbing porous membrane or beads (particulate adsorption material), is used.
Examples of such a protein-adsorbing material include protein-adsorbing porous membranes as described in Patent Literatures 1 to 5 and Non Patent Literature 1.
Recently, demand for antibody drugs has increased rapidly, and the mass production of proteins that become antibody drugs has been demanded. With rapid progress in culture technique, an improvement in the ability of the purification step has also become a problem. Particularly, an improvement in the ability of protein-adsorbing porous membranes capable of high flow rate treatment has been expected.